Apple MacBook Air 13.3 in. (Z0FS0LL/A) Mac Notebook

This machine is a work of art, form, and function.  I use to have an Dell XPS m1330 with 2.2 GHz, 4GB RAM, 128 MB Graphics, N-wireless, big, fast harddrive, and I basicly went down to the 1.6 GHz Mac Book Air with 2GB RAM and integrated graphics.
I work with computers for a living and I can tell you that I can't tell the difference at all in performance. 
I can stream movies from Netflix, videos from CNN, have all sorts of windows up and running and the thing just works.  No buffering, no lags, no complaints.
The specs look weak on paper but it certainly does not feel slow.  (I don't work on 3D graphics programs so I wouldn't go as far as to say that it can do the high end 3D stuff mac users love to do)
Like I said I bought refurbished and highly recommend buying refurbished from apple, it was $999.  At almost twice that price new ~$1700-1900 I would go with the regular mac book unless the 3 lb ultra portable aspect is a must have.